* Update to exim-4.20, featuring host of minor bugfixes and some feature
enhancements. Non-critical upgrade.
* Distribution site fixes and cleanups (somehow ommitted in prev delta).
* Put distribution files in a subdirectory.
* Optional support for exiscan-acl; exiscan is still the default.
I think the submitter is doing a great job.
PR: ports/52228
Submitted by: Oliver Eikemeier <eikemeier@fillmore-labs.com>

Update 4.10 -> 4.12:
For Exim, this includes an enormous number of fixes. Most of these are
for esoteric configurations, although if you're bitten by them, you're
bitten hard.
The fixes also include closing up a buffer overflow that is not believed
to be exploitable, and a format string vulnerability that was only
exploitable by an Exim admin user, but then provided root access.
For Eximon, this just rationalizes a patch we carried locally for ages.

I agree with the Exim community that the exim-4.xx has reached production
quality.
Move exim to exim-old for folks who need exim-3.xx, because the
configuration file for exim-4.xx is not backward compatible. Move
exim-devel to exim, removing NO_LATEST_LINK:
repo-copy exim -> exim-old
copy over exim-devel -> exim
retire exim-devel
Slave ports are intended for use with the exim port, as before, so they
now build and install for exim-4.xx.